Problem - even if you so called legitimize it governments are︃ utilizing tracing, that allows them at the whim to track the funds back and then︄ they can seize all the funds.
I.e right now the US wants BTC at neutral,︅ that means they will seize to secure their BTC and tax evasion is a easy︆ option, other countries will do the same, either for tax (EURO) or for BTC/Stock piling.︇
So you could get your funds out and then 10 yrs later be charged with︈ tax evasion, money laundering and have everything *your home* etc seized.
You fucked up, see︉ if you can pay tax for the initial 30k (you said you have 50k) with︊ fines that will cover that, and then your funds are clean, and you can then︋ (if you've not traded them) bring them out.
If you take out the 650k then︌ you are fucked.
If you pay the 30k + fines (plus possible prison) then your︍ funds should be clear of claim, and you can withdraw those and pay the taxes︎ on.